If you adopt egoism as your moral code, then "you believe that it is morally right to do whatever promotes your best interest".
Ethical egoism, the principle that holds that people should do what is to their greatest advantage. It contrasts from psychological egoism, which guarantees that individuals can just act to their greatest advantage. . Ethical egoism likewise varies from rational egoism, which holds that it is rational to act in one's self-interest. Ethical egoism holds, along these lines, that activities whose results will profit the practitioner can be viewed as moral in this sense.